Ultrasound tracking of medication delivery by medication injection devices

ABSTRACT

A medication injection device includes a plunger head having an elastomer housing that fits within a barrel. The plunger head includes an ultrasonic transducer that sends and receives ultrasonic signals in the form of ultrasonic waves, an antenna, a microcontroller that interfaces with the ultrasonic transducer and the antenna, and a power source that powers the microcontroller and the ultrasonic transducer. The ultrasonic transducer, the antenna, the microcontroller, and the power source may be at least partially encapsulated in the elastomer housing. The microcontroller may be programmed to measure echo times of the ultrasonic waves, compare consecutive echo times, and apply a compensation factor. The microcontroller may also be programmed to calculate a volume of medication dispensed from the barrel.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.15/790,932, filed on Oct. 23, 2017, which claims priority to U.S.Provisional Application No. 62/411,926 filed Oct. 24 2016. Both of theseapplications are hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates generally to the field of tracking ofmedication delivery using medication injection device, and moreparticularly, apparatuses and methods of improved ultrasound tracking ofmedication delivery by medication injection devices.

BACKGROUND DESCRIPTION

Measuring the quantity and recording the timing of a drug'sadministration is an integral part of many disease treatments. For manytreatments, to achieve the best therapeutic effect, specific quantitiesof a drug may need to be injected specific times of day. For example,individuals suffering from diabetes may be required to inject themselvesregularly throughout the day in response to measurements of their bloodglucose. The frequency and volume of insulin injections must becarefully tracked and controlled to keep the patient's blood glucoselevel within a healthy range. Currently, there are a limited number ofmethods or devices for automatically tracking the drug administrationwithout requiring the user to manually measure and record the volume,date, and time. A variety of glucose injection syringes/pens have beendeveloped, but there is much room for significant advancement in thetechnology in order to reduce the size, lower the cost, and enhance itsfunctionality, accuracy, and reliability thus making it a more viablelong-term solution. For example, current insulin pens are oftendisposable, but do not include dosage tracking. A smaller portion of themarket is composed of reusable pens which are more expensive, and stilldo not include good dosage-tracking capabilities.

SUMMARY

The present disclosure is directed to systems and methods of drugadministration using a syringe with a smart plunger head.

In one aspect, the present disclosure is directed to a plunger head fora medication injection device. The plunger head may include an elastomerhousing that fits within a barrel of the medication injection device.The plunger head may also include an ultrasonic transducer that sendsand receives ultrasonic signals in the form of ultrasonic waves, anantenna, a microcontroller that interfaces with the ultrasonictransducer and the antenna, and a power source that powers themicrocontroller and the ultrasonic transducer. The ultrasonictransducer, the antenna, the microcontroller, and the power source maybe at least partially encapsulated in the elastomer housing. Themicrocontroller may be programmed with instructions to measure echotimes of the ultrasonic waves and compare consecutive echo times and ifa change in distance corresponding to a change in the consecutive echotimes is indicative of an error, the microcontroller may apply acompensation factor to the change in distance. The microcontroller mayalso be programmed with instructions to calculate a volume of medicationdispensed from the barrel based on the change in distance of the plungerhead.

In another aspect, the present disclosure is directed to a method oftracking administering of a medication delivered by a medicationinjection device. The method may include depressing a plunger of themedication injection device and sending and receiving ultrasonic signalsin the form of ultrasonic waves from a plunger head installed within abarrel of the syringe. The method may also include measuring the echotimes of the ultrasonic waves, wherein the echo time is the time ittakes for an ultrasonic wave to travel through the medication to an endof a barrel, reflect, and return to the plunger head. The method mayfurther include comparing consecutive echo times and if a change indistance corresponding to a change in the consecutive echo times isindicative of an error, the microcontroller applies a compensationfactor to the change in distance. The method may also includecalculating a volume of the medication dispensed based on a distance theplunger head travels.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a medication injection device, whichincludes a plunger head according to an exemplary embodiment.

FIG. 2 is a schematic of the plunger head of FIG. 1.

FIG. 3 is a schematic illustrating the behavior of ultrasonic signalstransmitted by the plunger head of FIG. 2.

FIG. 4 is a flow chart illustrating a method of error checking andcorrecting performed by the plunger head of FIG. 2.

FIG. 5 is a perspective view of the medication injection device of FIG.1 communicating with a remote device, according to an exemplaryembodiment.

FIG. 6 is a flow chart illustrating a method of tracking administeringof medication by a medication injection device, according to anexemplary embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings. Where possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

FIG. 1 shows a perspective view of a medication injection device 10designed for ejecting a fluid. Medication injection device 10 mayinclude a barrel 12, a plunger 14, a needle 16, and a hub 18 connectingneedle 16 to barrel 12. Barrel 12 may be configured to contain a fluid,for example, a medication 20 and medication injection device 10 may beconfigured to dispense medication 20 from needle 16 when plunger 14 isdepressed. A standard medication injection device (e.g., a syringe)usually contains a plunger head at the end of the plunger that seals offthe open top of the barrel and forces the fluid out the needle when theplunger is depressed. The plunger head for a standard medicationinjection device is usually a unitary piece of molded plastic or rubber.

For medication injection device 10 shown in FIG. 1, the standard plungerhead has been replaced with a smart or intelligent plunger head 22 thatis configured to measure and register the quantity of medication 20administered and the date and time of administration. Plunger head 22may be installed in a standard medication injection device bywithdrawing plunger 14 and removing the standard plunger head andinstalling smart plunger head 22. In some embodiments, medicationinjection device 10 may be manufactured and supplied with a smartplunger head 22 preinstalled. Smart plunger head 22 may be referredherein as either smart plunger head 22 or plunger head 22.

Plunger head 22 may be sized to correspond with the size of barrel 12.For example, plunger head 22 may be formed to fit any size medicationinjection device 10. For example, plunger head 22 may be sized to fit a1 ml, 2 ml, 3 ml, 5 ml, 10 ml, 20 ml, 30 ml, or 50 ml medicationinjection device.

FIG. 2 shows a schematic of plunger head 22, according to an exemplaryembodiment. Plunger head 22 may include an ultrasonic transducer 24, amicrocontroller 26, a power source 28, and an antenna 30 (e.g., for nearfield communication (NFC), which in some embodiments may be atransceiver (e.g., for BLUETOOTH low energy (BLE) communication). Insome embodiments, the components of plunger head 22 may be at leastpartially encapsulated in an elastomer (e.g., rubber, ethylene propylene(EPM), nitrile rubber (NBR), ethylene propylene diene (EPDM),polybutadiene, and polyisoprene). Ultrasonic transducer 24 may beconfigured to send and receive ultrasonic signals. Microcontroller 26may be programmed with instructions to control the overall operation ofthe plunger head. Antenna 30 may be configured to wirelesslycommunication with a remote device (e.g., a smart phone, a glucosemonitor, an insulin pump, and a computer) using one or more wirelesscommunication methods. The one or more wireless communication methodsmay include, for example, radio data transmission, Bluetooth, BLE, NFC,infrared data transmission, electromagnetic induction transmission,and/or other suitable electromagnetic, acoustic, or optical transmissionmethods. Power source 28 may be configured to power ultrasonictransducer 24, microcontroller 26, and Antenna 30.

Microcontroller 26 may include one or more processors, including forexample, a central processing unit (CPU). The processors may include anysuitable type of commercially available processor or may be a customdesign. Microcontroller 26 may include additional components, forexample, non-volatile memory (e.g., a flash memory), volatile memory(e.g., a random access memory (RAM)), and other like components,configured to store information and/or programmed instructions).

In some embodiments, plunger head 22 may also include a crystaloscillator 32 configured to keep accurate time so that the date and timeof each injection may be accurately recorded and stored in memory ofmicrocontroller 26. Crystal oscillator may be, for example, a 32 KHZcrystal oscillator. In some embodiments, crystal oscillator 32 may beinternal to microcontroller 26. In some embodiments, an external highspeed RC oscillator (e.g., 10 MHZ) may be used to provide sufficienttime accuracy to measure the echo times.

Power source 28 may be any suitable power source. For example, powersource 28 may be a battery, a capacitor, or the like. In someembodiments, power source 28 may be rechargeable via wireless energytransmission, for example, inductive coupling, resonant inductivecoupling, radio frequency (RF) link, or the like. In some embodiments,power source 28 may be a non-rechargeable battery that is configured tolast the operational life of plunger head 22, for which the operationallife may be about 1 year, about 2 years, about 3 years, or more. Forexample, in some embodiments, power source 28 may be a watch battery. Insome embodiments, where plunger head 22 is a passive device as describedherein, power source 28 may be eliminated.

Antenna 30 may be used to communicate with a variety of remote devices(e.g., smart phones, glucose monitors, insulin pumps, computers, etc.).Plunger head 22 may transmit the information via any suitable wirelesscommunication method. For example, in some embodiments, plunger head 22may utilize radio data transmission, BLUETOOTH or BLE, NFC, infrareddata transmission or other suitable method. In some embodiments,information may also be wirelessly transmitted from a remote device toplunger head 22 via antenna 30. For example, the date and time may beset by writing to microcontroller 26 via the wireless communication.

As shown in FIG. 2, in some embodiments, plunger head 22 may alsoinclude force sensor 34. Force sensor 34 may be configured to detectwhen a force is applied to plunger head 22 via plunger 14, which forexample may indicate that dispensing of medication is being initiated.Force sensor 34 may be, for example, a simple spring-loaded switch thatis molded into the plunger head 22. In some embodiments, ultrasonictransducer 24 may be configured to function as a force sensor therebyeliminating the need for a separate force sensor 34. For example,ultrasonic transducer 24 may have a piezoelectric element that maydetect the dynamic changes in pressure when a user depresses the plunger14.

In some embodiments, as shown in FIG. 2, plunger head 22 may include atemperature sensor 36. Temperature sensor 36 may be configured tomeasure the temperature of medication 20. Microcontroller 26 may beconfigured to use the temperature of medication 20 to compensate forvariations in the temperature that would affect the speed of soundwithin the medication, thus improving the accuracy of the distance andvolume calculations. In some embodiments, microcontroller 26 may alsouse temperature sensor 36 to monitor the temperature of medication 20 toensure that the temperature of medication 20 stays within an acceptablerange. The efficacy of some medications is affected by temperature.

Ultrasonic transducer 24 may be an actuator, piezoelectric element, orspeaker-like voice coil configured to generate and send a pressure waveor ultrasonic signals in the form of ultrasonic waves. In someembodiments, ultrasonic transducer may be a resonant thickness-modetransducer. Ultrasonic transducer 24 may be sized to be slightly smallerthan the inner diameter of barrel 12. As shown in FIG. 3, ultrasonictransducer 24 may be configured to generate ultrasonic signals 25 (e.g.,radiated ultrasonic sound energy waves) and send the ultrasonic signals25 down barrel 12 toward hub 18 and needle 16. The frequency of theultrasonic signals 25 may be determined by the thickness of ultrasonictransducer 24. By vary the thickness of ultrasonic transducer 24 thefrequency of the ultrasonic signals 25 may be varied. For example, thefrequency range for the ultrasonic signals may range from about 2 MHz toabout 4 MHz, about 2 MHz to about 3 MHz, or about 3 MHz to about 4 MHz.In some embodiments, the static capacitance of the ultrasonic transducer24 may also be varied. For example, in some embodiments the staticcapacitance may be about 900 pF, about 800 pF, about 700 pF, or less.According to one illustrative embodiment, for an ultrasonic transducer24 having a static capacitance of about 900 pF, one ultrasonic pulse ofthe ultrasonic signals 25 may be generated by supplying about 3V toultrasonic transducer 24, which translates to about 4 nanoJoules (nJ) ofenergy per pulse. The energy per pulse may be reduced, for example, byreducing the static capacitance of ultrasonic transducer 24.

The ultrasonic signals 25 can travel through medication 20 along thelength of barrel 12 and bounce or reflect off an end 27 of barrel 12 andtravel back through medication 20 to plunger head 22. The reflectedultrasonic signals or ultrasonic echo can be received and detected byultrasonic transducer 24. A velocity V of sound in medication 20 may bea known value and thus a distance D can be calculated, according to theformula: D=Vt/2, very accurately where time t is the time it takes foran ultrasonic signal to travel down and back (i.e., 2 D) from ultrasonictransducer 24. In other words, distance D can be calculated based on themeasured time between when an ultrasonic signal 25 is transmitted byultrasonic transducer 24 and the ultrasonic echo is detected byultrasonic transducer 24, and that time is referred to herein as theecho time. As plunger head 22 is moved down barrel 12, distance D willdecrease along with the echo time and the volume of medication in barrel12. And by knowing the radius r of barrel 12 then the volume V ofmedication 20 dispensed may be calculated based on the change indistance D according to the formula: V=πr²D. A suitable sampling rate ofthe ultrasonic signals can be selected so that the displacement ofplunger head 22 can be accurately tracked regardless of the speed atwhich plunger 14 may be depressed. For example, in some embodiments, asuitable sampling rate may be about 100 ms, about 80 ms, about 60 ms,about 40 ms, about 20 ms, about 10 ms, or less than about 10 ms. Inother embodiments, the sampling rate may be slower to conserve batterylife. For example, the sampling rate may be about 1 second.

As shown in FIG. 3, in some embodiments, a porous membrane 29 may beplaced within barrel 12 at end 27. Porous membrane 29 may be designed toallow medication 20 to pass through while providing a surface with goodreflective properties for the ultrasonic signals 25 to reflect backtowards ultrasonic transducer 24. Utilizing porous membrane 29 mayimprove the accuracy of the echo detection and thereby the distance andvolume calculations. It is contemplated that other materials may be usedbesides a porous membrane. It is also contemplated that the geometry ofbarrel 12 at end 27 may dictate whether a porous membrane is needed. Forexample, in some embodiments the geometry of end 27 may be designed toproduce the desired reflective properties avoiding the need to employporous membrane 29.

Microcontroller 26 may be programmed with instructions to control theoperation of ultrasonic transducer 24. Microcontroller 26 may beprogrammed with instructions to calculate data representative of thequantity of medication 20 dispensed. For example, in some embodiments,microcontroller 26 may be programmed to detect and record the echo timesof the ultrasonic signals 25. Based on the echo times, microcontroller26 may calculate distance D and volume V. Microcontroller 26 may alsoproduce an echo time profile of the distance between ultrasonictransducer 24 (i.e., plunger head 22) and end 27. Based on the echo timeprofile of the distance, microcontroller 26 may be able to identify afirst distance Di or starting position (e.g., before medication 20 isdispensed), which may correspond with barrel 12 being filed and a seconddistance D2 or ending position (e.g., after medication 20 is dispensed),which may correspond with barrel 12 being empty. Microcontroller 26 maythen calculate the change in distance between D1 and D2 and based onthis total change in distance may calculate the total volume (i.e.,amount or quantity) of medication 20 dispensed. In some embodiments,incremental changes in distance D may be calculated, for example,between each ultrasonic signal 25, as plunger head 22 travels downbarrel 12, which may then allow for incremental changes in volume to becalculated. Therefore, the total distance traveled by plunger head 22and total volume dispensed may be calculated in one or more ways. Forexample, the total distance traveled and total volume dispensed may becalculated based on the starting position and the ending position or thetotal distance and total volume may be calculated by totaling theincremental measurements.

Ultrasonic transducer 24 and/or microcontroller 26 may be programmedwith instructions to perform various forms of signal conditioning toimprove the accuracy by which the echo time of the reflected ultrasonicsignals 25 are detected and measured. For example, as plunger head 22approaches end 27 of barrel 12, when dispensing medication 20, measuringthe echo time can become increasingly difficult as the echo time becomesshorter and shorter and are more susceptible to destructive (e.g.,multi-path) wave interference. Ordinarily, a front edge of eachreflected wave of the ultrasonic signal 25 may be used to measure theecho time. But, as plunger head 22 gets closer to end 27 destructiveinterference may cause the front edge of the reflected waves to becomedistorted (e.g., change shape or jump). When the front edge of thereflected wave jumps, this change may not be indicative of actualmovement of plunger head 22, but may instead be caused by destructive(e.g., multi-wave) interference. Therefore, if this movement isincorrectly identified as movement of plunger head 22, it can lead toinaccurate measurement of the volume of medication 20 remaining inbarrel 12 as well as the volume of medication 20 dispensed.

The front edges of the reflected waves may jump forward (e.g., early orback (e.g., late). When the front edges of the reflected waves jump, thejump will typically be equal to a wavelength of ultrasonic signal 25. Insome embodiments, the jump may be equal to an integer multiple of thewavelength (e.g., 2 wavelengths, 3 wavelengths, or more wavelengths).Therefore, in order to improve the accuracy of the echo timemeasurement, particularly when plunger head 22 approaches end 27,microcontroller 26 may be programmed with instructions to identify andcompensate for these jumps. It has been observed that it is about thefinal 20% of the travel distance of plunger head 22 that is increasinglyaffected by the destructive interference. Therefore, in someembodiments, microcontroller 26 may be programmed to start executing theinstructions that identify and compensate for these jumps when plungerhead 22 is down to about the last 20% of the travel distance. In otherembodiments, the instructions that identify and compensate for thesejumps may always be executing.

In order to identify and compensate for these jumps, microcontroller 26may be programmed to measure and track the echo time of each wave ofultrasonic signal 25. Microcontroller 26 may then compare the echo timeof consecutive echo times to calculate a change in echo times betweenthe consecutive echo times. In some embodiments, microcontroller 26 maycalculate a moving average of echo times (e.g., using a low-pass filter)and compare the consecutive measurements of the moving average. And, ifthe calculated change in distance corresponding to the change in theecho times is above a threshold value, then microcontroller 26 canidentify the latest echo time as an error. In some embodiments, thethreshold value may be equal to the wavelength of ultrasonic signals 25.When microcontroller 26 identifies an echo time as an error,microcontroller can apply (e.g., subtract or add) a compensation factor,depending on whether the jump was early or late, to the calculatedchanged in distance to correct the error. For example, when thethreshold value is one wavelength, the compensation factor may also beequal to one wavelength. In some embodiments, once the compensationfactor is applied, microcontroller 26 may use the corrected change indistance when calculating a total distance traveled by plunger head 22and total volume of medication dispensed.

When microcontroller 26 compares an echo time to the previous echo timeand the change in distance corresponding to the change in echo times isless than the threshold value (e.g., one wavelength of ultrasonic signal25), microcontroller 26 may be programmed to recognize this change indistance as actual movement of plunger head 22, which microcontroller 26may use to calculate the total distance traveled by plunger head 22 andtotal volume of medication dispensed.

Example 1, described below, provides some values and ranges for afunctional operation of medication injection device 10 and plunger head22, according to an exemplary embodiment.

EXAMPLE 1

According to Example 1, barrel 12 of medication injection device 10 issized to hold a volume of about 3 ml of medication 20 and configured toallow plunger head 22 to travel a distance D of about 42.5 mm.Microcontroller 26 is programmed to operate at sampling rate of 20 ms.Ultrasonic transducer 24 is constructed to generate the ultrasonicsignal 25 at a frequency of about 2.6 MHz. The wavelength of theultrasonic signals 25 will depend on the frequency and fluid (i.e.,medication 20), but for the purposes of Example 1, the medication isassumed to be water. Thus, at a frequency of about 2.6 MHz theultrasonic signals 25 will have a wavelength of about 0.57 mm. Whenplunger head 22 is positioned at its starting point, which correspondsto barrel 12 being filled with 3 ml of medication 20 (i.e., water), anecho time for the ultrasonic signals 25 is about 60 microseconds. Asplunger 14 is depressed causing plunger head 22 to travel down barrel12, the echo time decreases. When plunger head 22 reaches the end ofbarrel 12, the echo time is about 7 microseconds.

FIG. 4 illustrates an exemplary method 400 performed by microcontroller26 as plunger head 22 travels down barrel 12, which may correspond toExample 1. Exemplary method 400 can identify sampling errors caused bydestructive interference and corrects the errors. As plunger head 22travels down barrel 12, the method may begin by ultrasonic transducer 24sending and receiving ultrasonic signals 25 (Step 402). At step 404,microcontroller 26 may measure the echo times for the ultrasonic signals25. In some embodiments, microcontroller 26 may be sending ultrasonicsignals at a sampling rate of 20 ms, and after each sampling,microcontroller 26 may be programmed to calculate a change in echo timefor two consecutive echo times and calculate a change in distancecorresponding to the change in the two echo times (Step 406). If thecalculated change in distance between the consecutive echo times isabove a threshold value (e.g., a wavelength of the ultrasonic signals25) (Step 408: Yes), microcontroller 26 may proceed to step 410). Atstep 410, microcontroller can identify this change in distance betweenthe two echo times as an error. When microcontroller 26 identifies anerror, microcontroller 26 can apply (e.g., subtract or add) acompensation factor to the change in distance associated with thatsampling, depending on whether the jump was early or late, to correctfor the error (Step 412). For some embodiments, the compensation factormay be equal to one wavelength of electrical signals 25. Returning tostep 408, if the calculated change in distance between the consecutiveecho times is below a threshold value (Step 408: No), microcontroller 26may proceed to step 414. At step 414, microcontroller 26 may identifythis change in distance as actual movement of plunger head 22. At step416, microcontroller 26 may calculate the total change in distance ofplunger head 22 and total dispensed volume of medication 20.

Referring now to FIG. 5, plunger head 22 may transmit the amount ofmedication 20 dispensed along with the time and date it was dispensed toa remote device 50 (e.g., a smart phone, a glucose monitor, an insulinpump, and a computer) via one or more of the wireless communicationmethods. Plunger head 22 may have a unique identifier so remote device50 may be able to identify and process the information receivedproperly. Plunger head 22 may transmit this information to remote device50 immediately or shortly after the medication is administered orplunger head 22 may store the information until remote device 50 iswithin range. The information may be stored, for example, in memory ofmicrocontroller 26. In some embodiments, plunger head 22 may wait toinitiate transmitting of the information until initiated by remotedevice 50. For example, a user may initiate information retrieval onremote device 50. In some embodiments, remote device 50 may transmit theinformation to a caregiver (e.g., a doctor) or upload the information tothe cloud so it may be saved to the patient's medical history and may beaccessed by the caregiver. The ability of a caregiver or a patient toaccess and review the dose history may improve treatment. For example,the ability of a caregiver to review a diabetic insulin injectionhistory and continuous glucose measurement data may enable the caregiverto adjust the prescribed treatment to improve the therapeutic effect,for example, by better stabilizing the patient's glucose levels.

In some embodiments, microcontroller 26 may be configured to simplydetect the echo times of the ultrasonic signals 25 and transmit the echotimes to remote device 50 and the remote device may perform all thecalculations and signal conditioning operations in order to calculatethe volume of medication 20 dispensed.

Plunger head 22 described herein may be utilized for a variety ofmethods for tracking administering of a medication to a patientdelivered by a medication injection device. Various methods of utilizingplunger head 22 will now be explained with reference to FIG. 7. In someembodiments, the methods as described herein may be performed by acaregiver (e.g., a doctor or nurse) in a hospital or other inpatientsetting. In some embodiments, the methods as described herein may beperformed by a caregiver (e.g., a doctor, nurse, or parent) at home oroutside a hospital. In some embodiments, the methods as described hereinmay be performed by the patient. It is contemplated that the methodsdescribed herein may be performed in other settings by otherindividuals.

Plunger head 22 may be utilized for a method 600 of trackingadministering of a medication to a patient delivered by a medicationinjection device, according to an exemplary embodiment, as shown in FIG.6. Method 600 may incorporate method 400, as described herein, as asubpart of method 600.

In some embodiments, at step 602, method 100 may begin by installingplunger head 22 into barrel 12 of medication injection device 10 (e.g.,a disposable syringe). In some embodiments, medication injection device10 may be supplied with plunger head 22 already installed, therebyeliminating this step.

Next, at step 604, barrel 12 of medication injection device 10 may befilled with medication 20. Barrel 12 may be completely filled or onlypartially with medication 20. In some embodiments, medication injectiondevice 10 may be supplied prefilled with medication 20, therebyeliminating this step. In some embodiments, plunger head 22 may beconfigured to “wake up” in response to a force applied during thefilling, which may be detected by force sensor 34.

Once filled, at step 606, medication injection device 10 may then bepositioned for administration. For example, needle 16 may be insertedinto the skin of the patient or into a drug delivery port connected tothe patient. Once in position, plunger 14 of medication injection device10 may be depressed, which forces the medication 20 out the needle 16 asplunger head 22 is forced down barrel 12.

While plunger 14 is being depressed, plunger head 22 may send andreceive ultrasonic signals 25 in the form of ultrasonic waves viaultrasonic transducer 24, at step 608. Step 608 may correspond to step402 of method 400. Plunger head 22 may be configured to send and receiveultrasonic signals 25 the duration of the time, that plunger 14 is beingdepressed. Plunger head 22 may measure the echo times of the ultrasonicwaves, for step 610. Step 610 may correspond to step 404 of method 400.

At step 612, plunger head 22 may compare echo times, and if a change indistance calculated based on a change in the echo times is indicative ofan error, then plunger head 22 may apply a compensation factor to thechange in distance. Step 612 may correspond to steps 406, 408, 410, and412 of method 400. At step 614, the quantity of medication 20 dispensedmay be calculated based on the calculated distance the plunger head 22traveled. Step 614 may correspond to step 416 of method 400.

For some embodiments of method 600, the change in distance calculatedbased on a change in the echo times may be indicative of an error whenthe change in distance is equal to about one wavelength of theultrasonic waves. For some embodiments of method 600, at step 612,plunger head 22 may recognize the change in distance as an actualmovement of the plunger head when the change in distance calculatedbased on a change in the echo times is less than one wavelength of theultrasonic waves.

In some embodiments, method 600 may also include transmitting thequantity of the medication dispensed and the time and date the quantitywas dispensed to a remote device. In some embodiments, method 600 mayalso include uploading the quantity of the medication dispensed and thetime and date the quantity was dispensed to the cloud. In someembodiments, method 600 may also include sending the quantity of themedication dispensed and the time and date the quantity was dispensed toa caregiver.

The foregoing description has been presented for purposes ofillustration. It is not exhaustive and is not limited to precise formsor embodiments disclosed. Modifications, adaptations, and otherapplications of the embodiments will be apparent from consideration ofthe specification and practice of the disclosed embodiments. Forexample, the described embodiments of plunger head 22 may be adapted forused with a variety of medication injection devices, including forexample, syringes, auto-injectors, auto-syringes, injector pens (e.g.,insulin pens), or other drug or medication injection devices. Thedescribed embodiments of plunger head 22 may be also adapted for usewith a variety of other injection or dispensing devices, which may bemedical or non-medical related. For example, plunger head 22 may be usedin non-medical fluid dispensing applications where the measurement andtracking of the volume of fluid being dispensed is of interest.

Moreover, while illustrative embodiments have been described herein, thescope includes any and all embodiments having equivalent elements,modifications, omissions, combinations (e.g., of aspects across variousembodiments), adaptations and/or alterations based on the presentdisclosure. The elements in the claims are to be interpreted broadlybased on the language employed in the claims and not limited to examplesdescribed in the present specification or during the prosecution of theapplication, which examples are to be construed as nonexclusive.Further, the steps of the disclosed methods can be modified in anymanner, including reordering steps and/or inserting or deleting steps.

The features and advantages of the disclosure are apparent from thedetailed specification, and thus, it is intended that the appendedclaims cover all systems and methods falling within the true spirit andscope of the disclosure. As used herein, the indefinite articles “a” and“an” mean “one or more.” Similarly, the use of a plural term does notnecessarily denote a plurality unless it is unambiguous in the givencontext. Words such as “and” or “or” mean “and/or” unless specificallydirected otherwise. Further, since numerous modifications and variationswill readily occur from studying the present disclosure, it is notdesired to limit the disclosure to the exact construction and operationillustrated and described, and accordingly, all suitable modificationsand equivalents may be resorted to, falling within the scope of thedisclosure.

Computer programs, program modules, and code based on the writtendescription of this specification, such as those used by themicrocontrollers, are readily within the purview of a softwaredeveloper. The computer programs, program modules, or code can becreated using a variety of programming techniques. For example, they canbe designed in or by means of Java, C, C++, assembly language, or anysuch programming languages. One or more of such programs, modules, orcode can be integrated into a device system or existing communicationssoftware. The programs, modules, or code can also be implemented orreplicated as firmware or circuit logic.

Other embodiments will be apparent from consideration of thespecification and practice of the embodiments disclosed herein. It isintended that the specification and examples be considered as exampleonly, with a true scope and spirit of the disclosed embodiments beingindicated by the following claims.

1. A machine-accessible storage medium providing instructions that, whenexecuted by a medication injection device, will cause the medicationinjection device to perform operations comprising: sending ultrasonicsignals as ultrasonic waves from a plunger head into a barrel of themedication injection device; receiving reflections of the ultrasonicwaves from the barrel; measuring echo times of ultrasonic waves;comparing consecutive echo times of the ultrasonic waves to determine achange in distance travelled by the plunger head; assessing whether thechange in distance is deemed to be indicative of an error; applying acompensation factor to the change in distance when the change indistance is deemed to be indicative of the error; and calculating avolume of medication dispensed from the barrel based on the change indistance of the plunger head, as compensated by the compensation factorwhen the change in distance is deemed to be indicative of the error. 2.The machine-accessible storage medium of claim 1, wherein assessingwhether the change in distance is deemed to be indicative of the errorcomprises: identifying when the change in distance is greater than orequal to about one wavelength of the ultrasonic waves.
 3. Themachine-accessible storage medium of claim 2, wherein the compensationfactor is equal to about one wavelength of the ultrasonic waves.
 4. Themachine-accessible storage medium of claim 1, further providinginstructions that, when executed by the medication injection device,will cause the medication injection device to perform furtheroperations, comprising: determining that the change in distance is notindicative of the error when the change in distance is less than onewavelength of the ultrasonic waves.
 5. The machine-accessible storagemedium of claim 1, wherein the ultrasonic signals have a frequencybetween about 2 Mhz and about 3 Mhz.
 6. The machine-accessible storagemedium of claim 1, further providing instructions that, when executed bythe medication injection device, will cause the medication injectiondevice to perform further operations, comprising: starting to assesswhether the change in distance is deemed to be indicative of the erroronly after the plunger head reaches a last 20% of a total availabletravel distance of the plunger head within the barrel.
 7. Themachine-accessible storage medium of claim 1, further providinginstructions that, when executed by the medication injection device,will cause the medication injection device to perform furtheroperations, comprising: transmitting data indicative of the volume ofmedication dispensed from the barrel to a remote device via an antenna.8. The machine-accessible storage medium of claim 7, further providinginstructions that, when executed by the medication injection device,will cause the medication injection device to perform furtheroperations, comprising: registering a date and time the volume ofmedication is dispensed; and transmitting the date and time to theremote device along with the data indicative of the volume of medicationdispensed.
 9. The machine-accessible storage medium of claim 1, furtherproviding instructions that, when executed by the medication injectiondevice, will cause the medication injection device to perform furtheroperations, comprising: measure a temperature of the volume ofmedication with a temperature sensor; and compensating for changes inthe temperature of the volume of medication when calculating the volumeof medication dispensed.
 10. The machine-accessible storage medium ofclaim 1, wherein the medication injection device is at least one of adisposable syringe, an auto-injector, or an insulin pen.
 11. A method oftracking administration of a medication delivered by a medicationinjection device, the method comprises: depressing a plunger of themedication injection device; sending and receiving ultrasonic signals inthe form of ultrasonic waves from a plunger head installed within abarrel of the syringe; measuring the echo times of the ultrasonic waves,wherein the echo time is the time it takes for an ultrasonic wave totravel through the medication to an end of a barrel, reflect, and returnto the plunger head; comparing consecutive echo times and if a change indistance corresponding to a change in the consecutive echo times isindicative of an error, the microcontroller applies a compensationfactor to the change in distance; and calculating a volume of themedication dispensed based on a distance the plunger head travels. 12.The method of claim 11, wherein the change in distance corresponding tothe change in the consecutive echo times is indicative of an error whenthe change in distance is greater than or equal to about one wavelengthof the ultrasonic waves.
 13. The method of claim 12, wherein thecompensation factor is equal to about a wavelength of the ultrasonicwaves.
 14. The method of claim 11, further comprising identifying thechange in distance corresponding to the change in the consecutive echotimes as actual movement of the plunger head if the change in distanceis less than one wavelength of the ultrasonic waves.
 15. The method ofclaim 11, further comprising selectively transmitting wirelessly thevolume of the medication dispensed to a remote device.
 17. The method ofclaim 16, further comprising registering the date and time themedication is dispensed and transmitting the date and time to the remotedevice along with the volume of medication dispensed.
 18. The method ofclaim 11, wherein the medication injection device is a standarddisposable syringe, and the method further comprises installing theplunger head into the syringe prior to filing the barrel of the syringewith a medication.
 10. The method of claim 11, wherein the medicationinjection device is at least one of a disposable syringe, anauto-injector, or insulin pen.
 20. The method of claim 11, furthercomprising starting the comparing of consecutive echo times when theplunger head reaches the last 20% of a total available travel distance.